Abstract The reaction of o-azidobenzaldehyde 1 with TPP at 0 C leads to the expected iminophosphorane 2 and the indazole derivative 3 while at− 20 C the phosphazide 4 was the only reaction product. The close related compounds 2 and 4 shows stricking differences in reactivity towards primary amines.
[Luheshi, Abdul-Bassett N.; Salem, Salem M.; Smalley, Robert K.; Kennewell, Peter D.; Westwood, Robert Tetrahedron Letters, 1990 , vol. 31, # 45 p. 6561 - 6564]